JP2010279961A - Method of caulking jointing aluminum material and caulking jointed body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of caulking jointing an aluminum material by which joining strength is enhanced. <P>SOLUTION: This method of caulking jointing includes a grinding stage where aluminum alloy plates 2, 3 as the aluminum material are ground until at least a part of the oxidized films 8 on the jointed surfaces 11 of them are removed, and a jointing stage where the caulking jointing of the aluminum alloy plates 2, 3 are performed while pressurizing them. The aluminum alloy plates 2, 3 are rigidly jointed each other because the reproduced oxidized films 8c are broken on the jointed surface 11 between mutual aluminum alloy plates 2, 3 and the mutual aluminum alloy plates are adhered each other. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for caulking and joining caulked joints of stacked aluminum materials.

  Generally, the caulking joining technique joins members having plastic deformability by caulking. For example, in Patent Document 1 and Patent Document 2, a caulking joining technique in which a caulking cylinder made of a metal material is externally fitted to a pipe, and the caulking cylinder is plastically deformed so as to be recessed toward the pipe side to fix the caulking cylinder to the pipe. Is disclosed.

Conventionally, as a caulking joining technique between plate members, mechanical clinch joining such as spot clinching joining and Tox (registered trademark) joining is known (for example, see Patent Document 3). In this caulking and joining technique, the overlapped plate member is locally pushed by a punch with a die as a back support, and is plastically deformed so that the other plate member fits into one plate member to form an interlock. Is.
Such a caulking joining technique, unlike a joining technique such as spot welding, for example, requires less energy consumption for joining, and can cope with differences in the thickness of the joints. Widely used in fields such as building materials.

JP 11-311384 A JP 11-325360 A JP 2005-8953 A

  However, the conventional caulking joining technique (see, for example, Patent Document 3) has a problem that the joining strength is low as compared with the spot welding described above. Therefore, a caulking joining technique that further improves the joining strength over the conventional caulking joining technique is desired.

  The subject of this invention is providing the crimping joining method and crimping joining body of the aluminum material which can improve joining strength.

  As is well known, the surface of a commercially available aluminum plate is covered with an oxide film having a thickness of about 0.5 to 1.0 nm. Conventionally, it has been recognized that the presence of this oxide film does not adversely affect the bonding strength when aluminum plates are bonded together by welding, friction stir welding, caulking bonding, or the like. Moreover, even if the oxide film is removed from the surface of the aluminum plate, the new surface is oxidized with oxygen in the atmosphere and the oxide film is instantly regenerated. Therefore, conventionally, the oxide film is removed before joining the aluminum plates. It wasn't.

  When the present inventors have polished the surface of the aluminum material to remove the oxide film and then caulked and bonded the aluminum materials, even if an oxide film is formed on the surface of the new surface, the oxide film is broken and the new surface is broken. It was found that the interface between the aluminum materials disappeared due to the adhesion between the two materials, and the present invention was reached.

The method for caulking and joining aluminum materials according to the present invention, which solves the above problems, includes a polishing step of polishing until at least part of an oxide film on the joining surface of the aluminum materials is removed, and joining by caulking and joining the aluminum materials while applying pressure to each other. And a process.
In this caulking joining method, a new surface appears when the surface of the aluminum material is polished to remove the oxide film. When the polished aluminum materials are caulked and joined, even if the oxide film is regenerated on the new surface, the regenerated oxide film is broken and the new surfaces of the aluminum material adhere to each other. As a result, the aluminum materials in which the new surfaces are adhered to each other are firmly joined by the disappearance of the interface.
The reason why the oxide film regenerated on the new surface after polishing is easily broken during caulking is because the oxide film is thin and soft.

Further, such a caulking joining method can be configured to polish until the surface roughness of the joining surface of the aluminum material is 5.5 or less at the maximum height (Ry) in the polishing step.
In this caulking joining method, a fine uneven pattern is formed on the surface of the polished aluminum material. And in this caulking joining method, when the aluminum materials are overlapped, the surface roughness (Ry) is 5.5 or less, so that the projections of the concavo-convex patterns contact each other (area) ) Will increase.
As a result, in this caulking joining method, the soft oxide film regenerated after polishing is easily broken by contact between the convex parts, and the contact area between the new surfaces exposed by breaking the oxide film is also a place where the convex parts contact each other. Increased by increasing Therefore, according to this caulking joining method, the area where the aluminum materials adhere to each other at the joining surfaces of the aluminum materials increases, so that the aluminum materials are joined more firmly.

And the crimping joined body of the aluminum material of the present invention which solved the above-mentioned subject is a crimping joined body which crimped and joined the aluminum materials, and the new surfaces exposed on the surface of the aluminum material are adhered to each other It is characterized by.
In this caulking joined body, aluminum of each composition adheres to each other at the joining surface of the aluminum materials, so that the aluminum materials are firmly joined.

  According to the caulking bonding method and the caulking bonded body of the present invention, the bonding strength between aluminum materials can be improved.

(A) is a perspective view of the caulking joined body according to the present embodiment, a view having a cutout portion to show a cross section of the joined portion, (b) is a partially enlarged view of the I portion of (a), (C) is a figure which shows the crimping | jointing joined body as a comparative example, Comprising: It is a figure corresponding to the I section of (a). (A)-(e) is process drawing of the manufacturing method of the crimping joining body concerning this embodiment, and is a figure explaining the crimping joining method. (A) is a conceptual diagram which shows a mode that the aluminum alloys of an aluminum alloy plate adhere to each other in the process of the manufacturing method of the crimping joined body concerning this embodiment, (b) is a mode that aluminum alloy plates spring back. FIG. In Example 1- Example 9 of this invention, it is the graph which showed the relationship between the count of the paper file used for grinding | polishing of an aluminum alloy plate, and the surface roughness of the aluminum alloy plate after grinding | polishing, Ra is arithmetic mean roughness. Ry is the maximum height and Rx is the ten-point average roughness. (A) is an optical microscope photograph of the cross section of the crimped joint produced in Example 9 of the present invention, (b) is an enlarged photograph of the part where the arrow crosses in (a), and shows the joint between the aluminum alloy plates The enlarged photograph shown, (c) is a graph showing the result of EPMA (Electron Probe Micro. Analyzer) line analysis in the direction of the arrow in (a). It is a graph which shows the tensile shear strength of the crimping joining body produced in Example 1 to Example 9, and Comparative Example 1 and Comparative Example 2 of this invention. In Example 10 to Example 16 of the present invention, it is a graph showing the relationship between the count of the paper file used for polishing the aluminum alloy plate and the surface roughness of the polished aluminum alloy plate, Ra is the arithmetic average roughness Ry is the maximum height and Rx is the ten-point average roughness. It is a graph which shows the tensile shear strength of the crimped joining body produced in Example 10 to Example 16 and Comparative Example 3 of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
The present invention relates to a caulking joining method and caulking joined bodies between stacked aluminum materials, in which plate bodies and three-dimensional structures formed of pure aluminum or aluminum alloy are brought into contact with each other, and caulking joining is performed by caulking joining at the contact surfaces. Method and caulking assembly.
As shown in FIG. 1A, a caulking joined body 1 according to this embodiment is obtained by caulking and joining a first aluminum alloy plate 2 and a second aluminum alloy plate 3 made of an aluminum alloy. The first aluminum alloy plate 2 and the second aluminum alloy plate 3 correspond to “aluminum material” in the claims.
In the following description, when referring to both the first aluminum alloy plate 2 and the second aluminum alloy plate 3, they may be simply referred to as “aluminum alloy plates 2 and 3”.
There is no restriction | limiting in particular as said aluminum alloy, For example, 2000 series alloy (Al-Cu-Mg), 3000 series alloy (Al-Cu-Mg), 4000 series alloy (Al-Si), 5000 series alloy (Al-Mg). ), 6000 series alloy (Al—Mg—Si), 7000 series alloy (Al—Zn—Mg), and the like.

  The caulking joined body 1 is formed by plastically deforming the first aluminum alloy plate 2 and the second aluminum alloy plate 3 that are overlapped with each other so as to be locally depressed. A part is inserted into the second aluminum alloy plate 3 side. Incidentally, the depressed shape is circular in plan view.

This caulking joined body 1 has an interlock 5 bulged so that a portion of the first aluminum alloy plate 2 fitted on the second aluminum alloy plate 3 side spreads outward in the radial direction of the recessed hole 4. ing.
The caulking joined body 1 according to this embodiment is formed by locally plastically deforming and caulking the first aluminum alloy plate 2 and the second aluminum alloy plate 3 so as to form such an interlock 5. A joint portion 6 is formed.

  As shown in FIG. 1B, in such a joint portion 6, the aluminum alloys of the first aluminum alloy plate 2 and the second aluminum alloy plate 3 are adhered to each other. The interface between the aluminum alloy plate 2 and the second aluminum alloy plate 3 is observed to have disappeared by normal optical judgment. Incidentally, reference numeral 7 in FIG. 1B is a trace of an oxide film to be described later, and a two-dot chain line connecting the trace 7 represents the disappeared interface with a virtual line.

FIG.1 (c) referred here is a schematic diagram which shows the crimping | jointing joined body 20 as a comparative example, Comprising: It is a figure corresponding to FIG.1 (b).
As shown in FIG. 1C, a caulking joined body 20 as a comparative example is different from the caulking joined body 1 according to the present embodiment, and includes a first aluminum alloy plate 2 and a second aluminum alloy plate 3. An oxide film 8 is interposed between the oxide film 8 a of the first aluminum alloy plate 2 and an oxide film 8 b of the second aluminum alloy plate 3. ing.
Incidentally, the caulking joined body 1 according to this embodiment shown in FIGS. 1A and 1B is caulked and joined to the aluminum alloy plates 2 and 3 from which the oxide film 8 has been removed by polishing, as will be described below. The caulking joined body 20 shown in FIG. 1C is obtained by caulking and joining the aluminum alloy plates 2 and 3 without removing the oxide film 8.

Next, a method for caulking and joining aluminum alloy plates will be described while explaining a method for producing the caulking joined body 1 according to the present embodiment.
In this method, as shown in FIG. 2A, first, a pair of first aluminum alloy plate 2 and second aluminum alloy plate 3 are prepared. The thicknesses of these aluminum alloy plates 2 and 3 may be about 0.1 to 4.0 mm.
The surface of the aluminum alloy plates 2 and 3 has an oxide film 8 formed by oxidizing the aluminum alloy mainly with oxygen in the atmosphere. The thickness of the oxide film 8 is generally about 0.5 to 1.0 nm, but the range width is somewhat different depending on the composition of the aluminum alloy and the standing time (period) in the air.

Next, in this method, as shown in FIG. 2B, the aluminum alloy plates 2 and 3 are polished to remove the oxide film 8 (see FIG. 2A) to expose the new surface 10. This step corresponds to a “polishing step” in the claims.
In the present embodiment, the oxide film 8 is removed over the entire joining surface 11 of the aluminum alloy plates 2 and 3 (see FIGS. 2A and 2B). It is sufficient that the oxide film 8 is removed at least in part. The “joining surface 11” here corresponds to the joining surface referred to in the claims, and the contact surface portion between the aluminum alloy plates 2 and 3 forming the joining portion 6 (caulking portion) shown in FIG. Means.

In this polishing step, as described above, the oxide film 8 is removed, and the surfaces of the aluminum alloy plates 2 and 3 are polished so as to have a predetermined surface roughness (surface roughness). The surface roughness is preferably about 5.5 or less at the maximum height (Ry).
Incidentally, since the oxide film 8 is uniformly formed on the surfaces of the aluminum alloy plates 2 and 3 before polishing prepared first, the surface roughness is generally 2.5 (maximum height) (Ry). The surface is smoother than 5.5 (Ry) after polishing, but the new surface 10 (ground portion) of the aluminum alloy plates 2 and 3 from which the oxide film 8 has been removed is as described later. The surface roughness is adjusted between about 20 (Ry) and about 2 (Ry) depending on the degree of polishing.

As a method for polishing the surfaces of the aluminum alloy plates 2 and 3, the polishing may be performed manually using an abrasive or mechanical polishing.
As the above-mentioned abrasive, a paper file is desirable, and a paper file of # 80 to # 2000 can be suitably used with a count. It should be noted that water polishing may be performed as necessary when polishing.

  As shown in FIG. 2C, the oxide film 8c is instantaneously regenerated on the new surface 10 exposed by polishing (see FIG. 2B). The regenerated oxide film 8c is much thinner and softer than the oxide film 8 shown in FIG.

  Next, in this method, as shown in FIG. 2 (d), the aluminum alloy plates 2 and 3 are overlapped so that the polished surface side (regenerated oxide film 8c side) comes into contact with each other, and the aluminum alloy The plates 2 and 3 are arranged between the die 12 and the punch 13 constituting the caulking tool. The caulking tool including the die 12 and the punch 13 forms a circular recessed hole 4 shown in FIG. The sizes of the die 12 and the punch 13 can be appropriately set according to the thickness of the aluminum alloy plates 2 and 3, the diameter and depth of the recessed hole 4 (see FIG. 1A), and the like. Incidentally, in this embodiment, a commercially available die 12 and punch 13 are used, the inner diameter D1 of the die 12 is 8.0 mm, the hole depth H of the die 12 is 1.2 mm, and the outer shape of the punch 13 is D2 is 5.2 mm.

The pressure applied when the aluminum alloy plates 2 and 3 are pushed into the holes of the die 12 by the punch 13 can be appropriately set so as to be about 35 kN depending on the type of the aluminum alloy plates 2 and 3 to be used.
The step of pressing the aluminum alloy plates 2 and 3 into the holes of the die 12 corresponds to the “joining step” in the claims.

At this time, as shown in the upper part of FIG. 3 (a), the aluminum alloy plates 2 and 3 have surface protrusions 14 and 14 on which a concave and convex pattern is formed with a predetermined surface roughness (surface roughness) by polishing. They touch each other.
Then, the regenerated oxide film 8c of the projecting portions 14 and 14 in contact with each other is broken as described above, and as shown in the lower part of FIG. The aluminum alloy with the aluminum alloy plate 3 adheres to each other. Reference numeral 7 in the lower part of FIG. 3A is a trace of the oxide film 8c, and a two-dot chain line connecting the trace 7 represents the disappeared interface between the aluminum alloy plates 2 and 3 with a virtual line.

  Further, as the surface roughness (surface roughness) of the aluminum alloy plates 2 and 3 is reduced (smoothed), the number of contact points between the convex portions 14 and 14 shown in the upper part of FIG. 3A increases. . That is, there are many places where the regenerated oxide film 8c is broken, and the area where the aluminum alloys adhere to each other increases. Then, as will be described later, the present inventors critically joined the aluminum alloy plates 2 and 3 together when the surface roughness (surface roughness) is 5.5 or less at the maximum height (Ry). It was found that the strength increased further.

On the contrary, if the surface roughness (surface roughness) of the aluminum alloy plates 2 and 3 is too large as shown in the upper part of FIG. Become. That is, it is conceivable that the number of places where the oxide film 8c is broken is reduced, and the area where the aluminum alloys adhere to each other is reduced. For example, as shown in the lower part of FIG. 3B, when the surface roughness (surface roughness) of the aluminum alloy plates 2 and 3 is too large, the aluminum alloy plates 2 and 3 adhered by the springback are again brought into contact with each other. It is possible to leave.
Therefore, in this embodiment, when the surface roughness (Ry) is 5.5 or less, it is considered that the bonding strength between the aluminum alloy plates 2 and 3 is further increased.

  In this method, the aluminum alloy plates 2 and 3 pushed into the holes of the die 12 (see FIG. 2D) are plastically deformed while breaking the oxide film 8c regenerated as described above, and FIG. As shown in FIG. 3, the interlocked body 5 is formed to complete the caulking joined body 1.

According to the caulking joining method as described above and the caulking joined body 1 obtained by this method, the new surfaces 10 and 10 of the aluminum alloy plates 2 and 3 adhere to each other. As a result, the aluminum alloy plates 2 and 3 to which the new surfaces 10 and 10 are adhered are firmly joined together by the disappearance of the interface.
Therefore, according to this caulking joining method and caulking joined body 1, the joining strength between the aluminum alloy plates 2 and 3 can be improved.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, It can implement with a various form.
In the above-described embodiment, the caulking bonding in which the aluminum alloy plates 2 and 3 are not broken is described assuming spot clinching bonding and Tox (registered trademark) bonding. However, the present invention describes an aluminum alloy plate such as burring bonding. It may be a caulking joint in which a rupture portion such as a hole is formed in a part of two or three.

  Further, in the above-described embodiment, the caulking joining method and the caulking joined body for caulking and joining the plate bodies have been described. However, the present invention may be performed by caulking and joining the three-dimensional structures other than the plate bodies. . Such a three-dimensional structure is not particularly limited as long as a predetermined contact surface can be secured so as to define the above-described joining surface, and may be a tubular body or the like.

  Moreover, although the said embodiment demonstrated what crimped and joins a pair of board body, this invention may overlap and caulk and join three or more members.

Next, the present invention will be described more specifically with reference to examples.
(Example 1 to Example 9, and Comparative Example 1 and Comparative Example 2)
In this example and this comparative example, using a 5000 series aluminum alloy plate (5052), the caulking joined body 1 (Example 1 to Example 9) shown in FIGS. 1A and 1B and FIG. The caulking joined body 20 (Comparative Example 1 and Comparative Example 2) shown in c) was produced. The size of the 5000 series aluminum alloy plate was 40 mm × 125 mm × 1.2 mm. In addition, a Tox (registered trademark) press caulking machine manufactured by Tox-Rix Pressotechnics was used for caulking. The applied pressure was adjusted by an automatic adjusting mechanism attached to the press caulking machine so that the total thickness after caulking was 0.7 mm.

  In Examples 1 to 9, the oxide film was removed by polishing the entire surface of the aluminum alloy plate in the polishing direction shown in Table 1 below. At this time, the count of the paper file used for polishing is shown in Table 1.

For Comparative Example 1, only the degreasing cleaning was performed without polishing the aluminum alloy plate. In Comparative Example 2, only the oil application was performed without polishing the aluminum alloy plate.
And the surface roughness of the aluminum alloy plate after grinding | polishing was measured. Surface roughness is JIS B
Based on 0601-1994, arithmetic average roughness (Ra), maximum height (Ry) and ten-point average roughness (Rx) were measured. Further, the surface roughness of the aluminum alloy plate subjected to only degreasing cleaning in Comparative Example 1 was also measured. The results are shown in Table 1. The relationship between the count of the paper file and the surface roughness at this time is also shown in FIG.

In the crimped joints produced in Examples 1 to 9, the new surfaces of the aluminum alloy plates were adhered to each other.
FIG. 5 (a) is an optical micrograph of a cross section of the crimped joint produced in Example 9, and FIG. 5 (b) is an enlarged photograph of the portion where the arrow crosses in FIG. 5 (a). FIG. 5C is a graph showing the result of EPMA (Electron Probe Micro. Analyzer) line analysis in the direction of the arrow in FIG. 5A, and the horizontal axis is FIG. The measurement position along the arrow direction of (a) is represented, and a vertical axis | shaft represents the intensity | strength (cps: countspersecond) per unit time.

In the caulking joined body of the present invention, as shown in FIGS. 5A and 5B, aluminum alloys are adhered to each other. And it is the chart as a result of conducting an EPMA (Electron Probe Micro.Analyzer) line analysis in the part (the part where the interface has disappeared) where the aluminum alloys are adhered and the aluminum alloy plates are in close contact with each other. As shown in FIG.5 (c), the component (metal oxide) which comprises an oxide film was not confirmed.
On the other hand, in Comparative Example 1 and Comparative Example 2, it was confirmed that an oxide film intervenes between aluminum alloy plates.

Next, the bonding strength was measured for each of the crimped joints produced in Examples 1 to 9 and Comparative Examples 1 and 2.
For the bonding strength, tensile shear strength was measured. The result is shown in FIG. Moreover, the percentage of the tensile shear strength obtained in Examples 1 to 9 and Comparative Example 2 when the tensile shear strength obtained in Comparative Example 1 is 100% is also shown in FIG. These percentages are shown in Table 1 as “Improvement rate of tensile shear strength (%)”.

(Examples 10 to 16 and Comparative Example 3)
In this example and this comparative example, a 6000 series aluminum alloy plate (6022) having the same size as the above 5000 series aluminum alloy plate was used.
In Example 10 to Example 16, the oxide film was removed by polishing the entire surface of the aluminum alloy plate in the polishing direction shown in Table 2 below. At this time, the count of the paper file used for polishing is shown in Table 2.

For Comparative Example 3, only the degreasing cleaning was performed without polishing the aluminum alloy plate.
Then, the surface roughness of the polished aluminum alloy plate was measured in the same manner as in Examples 1 to 9. The results are shown in Table 2. The relationship between the count of the paper file and the surface roughness at this time is also shown in FIG.

  And in the present Example and this comparative example, the caulking joined body was produced similarly to having mentioned above except having used the aluminum alloy plate shown in Table 2.

In the crimped joints produced in Examples 10 to 16, the new surfaces of the aluminum alloy plates were adhered to each other.
On the other hand, in the caulking joined body of Comparative Example 3, it was confirmed that an oxide film was interposed between the aluminum alloy plates.

  Next, the tensile shear strength was measured in the same manner as described above for each of the crimped joints produced in Examples 10 to 16 and Comparative Example 3. The result is shown in FIG. In addition, the percentage of the tensile shear strength obtained in Examples 10 to 16 when the tensile shear strength obtained in Comparative Example 3 is 100% is also shown in FIG. These percentages are shown in Table 2 as “Improvement rate of tensile shear strength (%)”.

(Evaluation results of Examples and Comparative Examples)
As shown in FIGS. 6 and 8, the crimped joints produced in Examples 1 to 16 were superior in tensile shear strength to the crimped joints produced in Comparative Examples 1 to 3. This is considered to be due to the fact that the oxide film was removed from the aluminum alloy plate by polishing, and the new surfaces of the aluminum alloy plate adhered to each other.

  In particular, as shown in Tables 1 and 2, the crimped joints of Examples 2 to 9 and Examples 11 to 16 having a surface roughness (Ry) of 5.5 or less are further improved in bonding strength. It was confirmed that

DESCRIPTION OF SYMBOLS 1 Caulking joined body 2 1st aluminum alloy plate (aluminum material)
3 Second aluminum alloy plate (aluminum material)
6 Bonding portion 8 Oxide coating 8c Oxide coating 10 New surface 11 Bonding surface 12 Die 13 Punch

Claims (3)

A polishing step of polishing until at least part of the oxide film on the bonding surface of the aluminum material is removed;
A joining step of caulking and joining the aluminum materials while pressing;
A method for caulking and joining aluminum materials, comprising:   2. The method of caulking and joining aluminum materials according to claim 1, wherein in the polishing step, polishing is performed until the surface roughness of the joining surface of the aluminum material becomes 5.5 or less in maximum height (Ry). It is a caulking joined body obtained by caulking and joining aluminum materials,
A new caulked joint of aluminum material, wherein the new surfaces exposed on the surface of the aluminum material are adhered to each other.